21
unperturbed(adjective, calm, quiet, cool, easy)
18
even-tempered(adjective, calm, quiet, smooth, easy)
18
nonchalant(adjective, feature, state, calm, quiet)
17
easy(adjective, feature, state, calm, quiet)
17
restful(adjective, calm, quiet, cool, secure)
17
unflappable(adjective, calm, quiet, cool, moderate)
16
mild(adjective, feature, state, calm, quiet)
16
quiescent(adjective, calm, quiet, cool, smooth)
16
smooth(adjective, calm, quiet, light, cool)
14
equable(adjective, calm, quiet, cool, kind)
14
gentle(adjective, calm, quiet, light, cool)
13
impassive(adjective, calm, quiet, cool, moderate)
12
cool-headed(verb, adjective, calm, quiet, cool)
12
halcyon(adjective, calm, quiet, cool, smooth)
11
controlled(adjective, unexcitable)
11
self-controlled(adjective, calm, close, quiet, gentle)
11
sober(adjective, calm, dull, quiet, cool)
10
patient(verb, adjective, calm, quiet, cool)
10
confident
10
easy-going(adjective, feature, state, calm, quiet)
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APASmart Define. (2015). serene thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/serene/thesaurus/synonyms
ChicagoSmart Define. 2015. "serene thesaurus" https://smartdefine.org/serene/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, serene thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/serene/thesaurus/synonyms>.
MLASmart Define. "serene thesaurus" 10 April 2015. Web. 24 September 2026. <https://smartdefine.org/serene/thesaurus/synonyms>